Sorry for the late response! I believe LFOLED is the one that needs to be hooked up to the CDS cell, though I'm not 100% sure. You can try hooking up each LED to see what it does and if it is a desirable effect. Who knows? Maybe you'll find an unintended cool effect...

Like I said in my previous response, the problem is that the Arduino sequentially loops through the program waiting for a piezo hit, and when it detects one, it breaks the loop to play the sound that was hit. In that case, the Arduino is no longer checking for other hits, which is why two sounds can't be played simultaneously. I put some possible solutions in the reply to your last comment.

Hello, doing two things at the same time on any processor is usually a problem, especially on microcontrollers like the Arduino. While I can't diagnose the exact problem without seeing the actual source code, I would imagine that the problem is that the Arduino sequentially loops through the program waiting for a piezo hit, and when it detects one, it breaks the loop to play the sound that was hit. In that case, the Arduino is no longer checking for other hits, which is why two sounds can't be played simultaneously. There are a few ways to fix this problem: although inefficient, a hardware solution would be to make each sound its own Arduino; a different solution would be to fiddle with the code to see if it can also check for double piezo hits. While I can help with the problem, I curr...

Hello, doing two things at the same time on any processor is usually a problem, especially on microcontrollers like the Arduino. While I can't diagnose the exact problem without seeing the actual source code, I would imagine that the problem is that the Arduino sequentially loops through the program waiting for a piezo hit, and when it detects one, it breaks the loop to play the sound that was hit. In that case, the Arduino is no longer checking for other hits, which is why two sounds can't be played simultaneously. There are a few ways to fix this problem: although inefficient, a hardware solution would be to make each sound its own Arduino; a different solution would be to fiddle with the code to see if it can also check for double piezo hits. While I can help with the problem, I currently have limited access to a computer (on vacation for the next two weeks), so it might take a while before I can look in depth into any programming heavy problems.

Sorry for the delayed response! I got caught up in a bunch of stuff and I didn't have much time to respond. Either way, here goes:1. It's actually the same Op Amp chip, but two different op amps. There are two amplifiers inside the TLC2262, and you can see them in the data sheet here on page 3. All you have to do is wire it up properly (e.g. the photocell and C2 before the second op amp).2.Yes, the Arp Switch is connecting the circuit to ground. In that specific case, the Analog pin is acting as a digital input, so grounding it pulls the pin to 0 volts, which is detected by the Arduino.3. Not really a mistake. The LFO LED [2] is really just a visual repeat of what is being set over IR, for confirmation that the IR is working, if you choose to use it.4. In short, I advise you not to chan...

Sorry for the delayed response! I got caught up in a bunch of stuff and I didn't have much time to respond. Either way, here goes:1. It's actually the same Op Amp chip, but two different op amps. There are two amplifiers inside the TLC2262, and you can see them in the data sheet here on page 3. All you have to do is wire it up properly (e.g. the photocell and C2 before the second op amp).2.Yes, the Arp Switch is connecting the circuit to ground. In that specific case, the Analog pin is acting as a digital input, so grounding it pulls the pin to 0 volts, which is detected by the Arduino.3. Not really a mistake. The LFO LED [2] is really just a visual repeat of what is being set over IR, for confirmation that the IR is working, if you choose to use it.4. In short, I advise you not to change it, because the way the code is set up is somewhat confusing, especially if you aren't too experienced in Arduino or other coding languages. However, if you do want to have a look, I believe the key assignments are under the Key.ino file where it says keysb = (PINB & B00010111);

No, I didn't encounter this issue when making this. Are you using a Rail to Rail Op Amp?If so, then my next best bet would be to check your wiring, specifically the speaker connection. In other previous projects I did encounter an issue where the output was virtually non-existent unless hooked up to a huge amplifier. After some troubleshooting I found that the speaker output had a poor connection to ground. So maybe check that with a continuity meter or something similar.

If you look closely on the ATMega chip, you'll notice that on the chip, +5V is hooked up to VCC. Since, they're connected, it's the same thing.

Hello! Yes, the alligator clip is indeed mainly used to hold the note. Essentially, the pad is a Digital I/O on the Arduino, and the alligator clip is grounding it, much like a switch. You could easily replace the alligator clip and keypad set-up with buttons by connecting the Digital I/O on the Arduino to one end and ground to the other. On the other hand, if you would like to do capacitive sensors with only one pin, that may require more circuitry. You can look to this project some ideas.

Haha, I try my best to respond to all types of questions, but I do miss a few here and there